ADO.NET 用windows方式连接数据库以及简单的增，删，改，查询操作

 

 static void Main(string[] args)        {            //Program p = new Program();            //p.Open();            //Open1();            //AddRecord();            QuerySingle();        }        public static string conStr = @"server=.\SQLEXPRESS;database=mydb2;Integrated Security=True;";        #region 1.成员方式打开数据库        /// <summary>        /// 成员方式        /// </summary>        public void Open()        {            string connstr = @"server=.\SQLEXPRESS;database=mydb2;Integrated Security=True";            SqlConnection conn = new SqlConnection();//创建数据库连接            conn.ConnectionString = connstr;            conn.Open();//打开数据库            Console.WriteLine("打开成功");            conn.Close();//关掉数据库         }                #endregion        #region 2.静态方法，直接调用就可以        /// <summary>        /// 静态方法，直接调用就可以        /// </summary>        public static void Open1()        {            string connstr = @"server=.\SQLEXPRESS;database=mydb2;Integrated Security=True";            SqlConnection conn = new SqlConnection(connstr);            conn.Open();            conn.Close();            Console.WriteLine("1111");              }         #endregion        #region 3.增加。删除，修改        /// <summary>        /// 增加，删除，修改都是用sqlCommand的ExecuteNonQuery        /// </summary>        public static void AddRecord()        {            SqlConnection conn = new SqlConnection(conStr);            conn.Open();            string cmdStr = "insert into category(C_Name,C_Remark)values('英语','这也太难了吧')";            SqlCommand cmd = new SqlCommand(cmdStr, conn);            int res = -1;//看影响的行数有多少            res = cmd.ExecuteNonQuery();            if (res > 0)            {                Console.WriteLine("增加成功");            }            else Console.WriteLine("增加失败");            conn.Close();//关掉数据库         }         #endregion        #region 4.查询并返回记录中的第一行，第一列的值        /// <summary>        /// 查询，并返回结果集中的第一行，第一列        /// </summary>        public static void QuerySingle()        {            SqlConnection conn = new SqlConnection(conStr);            conn.Open();            string cmdStr = "select * from category";            SqlCommand cmd = new SqlCommand(cmdStr, conn);            object obj = cmd.ExecuteScalar();            Console.WriteLine(obj);            conn.Close();//关掉数据库         }         #endregion